Besides the obvious privacy concerns, I'm worried about dangers from it being invoked by someone else within voice range. I've always thought that's why the current Siri has limited abilities.

I'm sure it won't be long before we see apps that listen, record any "Hey Siri" they hear, and then synthesize that voice to give your phone commands to "tell me my passwords", or more insidious and difficult-to-detect commands.

It seems Apple's new version will be facing this problem too.